Mollusca

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Arthropoda
Mollusca
Echinodermata
Cnidaria

The size of the phylum Mollusca is second only to the phylum Arthropoda. Members of the Mollusca phylum includes snails and clams as well as large animals such as octopuses and squids.  The octopuses and squids in particular are known to be quite intelligent species.

All members of the Mollusca phylum have a soft body with either an external or an internal shell for protection. Their soft bodies are composed mainly of water; hence, the majority of the mollusks are marine animals. Although a snail looks quite different from an octopus, there are many characteristics that they share. Below is a list of some of the common characteristics shared by this diverse looking group.

Characteristics:
bulletSoft bodied
bulletMuscular foot
bulletRadula - a rasping tongue

Marine Invertebrates Belonging to this Phylum:
bulletclams
bulletchitons
bulletsquids
bulletoctopuses
bulletsnails
bulletnudibranchs (a.k.a. sea slugs)

The sea slugs are unique in a way that they use bright colours as a defense mechanism. The vivid colours on their bodies advertise to potential predators that they are either poisonous or bad-tasting. 

Radula - the tongue of the Mollusks closely resembles a nail filer. Snails (i.e. Moon Snails) use their radula to bore holes into clam shells to access the flesh inside. If you ever take a stroll along the beach and discover clam shells with perfect round holes drilled into them, that would most likely to be the handy work of another mollusk. 

Figure - A chiton carries its protective plates on top of its body. Chitons are capable of clinging onto rocks with extremely powerful suction; hence, enable them to withstand the crushing waves.

bulletDid you know...the largest invertebrate specie of the world belongs to the Phylum Mollusca? 
The Giant Squid can weigh up to 2 tonnes and reach 17 metres in length. 

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March 25, 2004